PURPOSE: To examine the effects of perfluorocarbon liquid (PFCL) and silicone oil (SO) on human retinal pigment epithelium (RPE) cells and retinal ganglion cells (RGCs) in vitro. METHODS: Human RPE cells (ARPE-19 cells), seeded on microporous inserts, were exposed to PFCL or SO and incubated for 3 or 7 days. Perfluorocarbon liquid was in contact with cells at the apical or baso-lateral side, not inhibiting cell feeding. Then, the quantification of cell proliferation and cell viability were evaluated by WST-1 assay. In the same way, RGCs were exposed for 1 hour or 3 days, and the number of viable RGCs was counted by using a fluorescence viability agent. RESULTS: Perfluorocarbon liquid affected the survival of ARPE-19 cells and RGCs when compared with the nontreated control group. ARPE-19 cells decreased significantly after being in contact with PFCL at the baso-lateral side for 7 days. However, PFCL contact at the apical side reduced the number of RGCs in a time-dependent manner. In case of SO, the viability of the ARPE-19 cells decreased significantly after being in contact with SO at the baso-lateral side for 7 days. However, SO did not reduce the number of RGCs after a 3-day exposure. CONCLUSION: Perfluorocarbon liquid is directly toxic to ARPE-19 cells when exposed to the cells for 7 days. On the contrary, it seems that RGCs are damaged in a time-dependent manner by the more mechanical rather than toxic effects of PFCL. Silicone oil seems to exert mechanical rather than toxic effects on ARPE-19 cells. When PFCL is used as a postoperative tamponade clinically, understanding the difference in the effects will lead to more effective and safer results.